Liquid crystal display device

Abstract

Disclination of an active matrix liquid crystal display device is reduced. Portions of pixel electrodes are formed so as to mutually overlap with a convex portion. If the height of the convex portion is too tall, the amount of light leakage increases due to liquid crystals orienting diagonally with respect to a substrate surface. (See FIG. 1 C.) If the height of the convex portion is low, the disclination reduction effect is low. The optimal convex portion height is thus determined.

What is claimed is: 
     
       1. A liquid crystal display device comprising:
 a thin film transistor comprising a semiconductor layer over a substrate; 
 a gate wiring comprising a conductive material, and a pattern comprising the conductive material over the substrate; 
 a source wiring over the gate wiring and the pattern; 
 a convex portion over the substrate, and comprising a first portion in parallel with the gate wiring, and a second portion in parallel with the source wiring; and 
 a pixel electrode electrically connected to the thin film transistor, and partially overlapped with the convex portion; 
 wherein an edge of the pixel electrode and the second portion are overlapped with each other, 
 wherein the first portion intersects with the source wiring, 
 wherein the convex portion comprises the pattern, and 
 wherein the semiconductor layer is not overlapped with the second portion. 
 
     
     
       2. A liquid crystal display device comprising:
 a pixel portion over a substrate, and comprising: 
 a first thin film transistor comprising a semiconductor layer over the substrate; 
 a gate wiring comprising a conductive material, and a pattern comprising the conductive material over the substrate; 
 a source wiring over the gate wiring and the pattern; 
 a convex portion over the substrate, and comprising a first portion in parallel with the gate wiring, and a second portion in parallel with the source wiring; and 
 a pixel electrode electrically connected to the first thin film transistor, and partially overlapped with the convex portion; 
 a driver circuit over the substrate, and comprising a second thin film transistor, 
 wherein an edge of the pixel electrode and the second portion are overlapped with each other, 
 wherein the first portion intersects with the source wiring, 
 wherein the convex portion comprises the pattern, and 
 wherein the semiconductor layer is not overlapped with the second portion. 
 
     
     
       3. A liquid crystal display device comprising:
 a thin film transistor comprising a semiconductor layer over a substrate; 
 a gate wiring comprising a conductive material, and a pattern comprising the conductive material over the substrate; 
 a source wiring over the gate wiring and the pattern; 
 a convex portion over the substrate, and formed comprising a first portion in parallel with the gate wiring, and a second portion in parallel with the source wiring; and 
 an insulating film over the thin film transistor; 
 a pixel electrode over the insulating film, electrically connected to the thin film transistor, and partially overlapped with the convex portion; 
 wherein an edge of the pixel electrode and the second portion are overlapped with each other, 
 wherein the first portion intersects with the source wiring, 
 wherein the convex portion comprises the pattern, and 
 wherein the semiconductor layer is not overlapped with the second portion. 
 
     
     
       4. A liquid crystal display device according to  claim 1 , wherein the convex portion is provided over an insulating film. 
     
     
       5. A liquid crystal display device according to  claim 2 , wherein the convex portion is provided over an insulating film. 
     
     
       6. A liquid crystal display device according to  claim 3 , wherein the convex portion is provided over the insulating film. 
     
     
       7. A liquid crystal display device according to  claim 1 , further comprising a storage capacitor over the substrate, and comprising a first electrode comprising the semiconductor layer, a second electrode comprising a gate electrode of the thin film transistor, and an dielectric film comprising a gate insulating film of the thin film transistor. 
     
     
       8. A liquid crystal display device according to  claim 2 , further comprising a storage capacitor over the substrate, and comprising a first electrode comprising the semiconductor layer, a second electrode comprising a gate electrode of the thin film transistor, and an dielectric film comprising a gate insulating film of the thin film transistor. 
     
     
       9. A liquid crystal display device according to  claim 3 , further comprising a storage capacitor over the substrate, and comprising a first electrode comprising the semiconductor layer, a second electrode comprising a gate electrode of the thin film transistor, and an dielectric film comprising a gate insulating film of the thin film transistor. 
     
     
       10. A liquid crystal display device according to  claim 1 , wherein the convex portion comprises a film selected from the group consisting of a photosensitive organic resin film, an organic resin film, a silicon oxide film, a silicon nitride film and a silicon oxynitride film. 
     
     
       11. A liquid crystal display device according to  claim 2 , wherein the convex portion comprises a film selected from the group consisting of a photosensitive organic resin film, an organic resin film, a silicon oxide film, a silicon nitride film and a silicon oxynitride film. 
     
     
       12. A liquid crystal display device according to  claim 3 , wherein the convex portion comprises a film selected from the group consisting of a photosensitive organic resin film, an organic resin film, a silicon oxide film, a silicon nitride film and a silicon oxynitride film. 
     
     
       13. A liquid crystal display device according to  claim 1 , wherein a taper angle of the convex portion is less than 90°. 
     
     
       14. A liquid crystal display device according to  claim 2 , wherein a taper angle of the convex portion is less than 90°. 
     
     
       15. A liquid crystal display device according to  claim 3 , wherein a taper angle of the convex portion is less than 90°. 
     
     
       16. A liquid crystal display device according to  claim 1 , wherein the liquid crystal display device is a reflective type liquid crystal display device. 
     
     
       17. A liquid crystal display device according to  claim 2 , wherein the liquid crystal display device is a reflective type liquid crystal display device. 
     
     
       18. A liquid crystal display device according to  claim 3 , wherein the liquid crystal display device is a reflective type liquid crystal display device. 
     
     
       19. A liquid crystal display device according to  claim 1 , wherein the liquid crystal display device is a transmission type liquid crystal display device. 
     
     
       20. A liquid crystal display device according to  claim 2 , wherein the liquid crystal display device is a transmission type liquid crystal display device. 
     
     
       21. A liquid crystal display device according to  claim 3 , wherein the liquid crystal display device is a transmission type liquid crystal display device. 
     
     
       22. A liquid crystal display device according to  claim 1 , wherein the liquid crystal display device is applied to an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head mounted display, a mobile computer, a portable telephone and an electronic notebook. 
     
     
       23. A liquid crystal display device according to  claim 2 , wherein the liquid crystal display device is applied to an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head mounted display, a mobile computer, a portable telephone and an electronic notebook. 
     
     
       24. A liquid crystal display device according to  claim 3 , wherein the liquid crystal display device is applied to an electronic equipment selected from the group consisting of a video camera, a digital camera, a projector, a head mounted display, a mobile computer, a portable telephone and an electronic notebook.